This not only resulted in a seriously padded HTML, it was also generating validation problems, causing Google Reader to reject the post and not display it at all.

Solution? Nuking by regular expression. I replaced all the "<td [^>]+>" instances with "<td>", and I had a seriously trimmed table from 116Kb (!) to 7Kb. After that, Google picked the post within seconds....

Lesson? Never, ever use an Excel-generated table in Blogger. Or if you need to do that, make sure to remove all the fat...